U.S. Pat. No. 4,278,589 describes the preparation of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole and 2-(2-hydroxy-3-tert-octyl-5-.alpha.-cumylphenyl)-2H-benzotriazole. U.S. Pat. No. 4,278,589 also describes the preparation of 2-(2-hydroxy-3,5-di-.alpha.-cumylphenyl)-2H-benzotriazole. This latter compound is a very effective UV absorber, but unfortunately is relatively insoluble being soluble only at about the 14% (by weight) level in xylene. Since such aromatic solvents are threatened with banning because of environmental concerns, a diligent search for an effective benzotriazole which has the general light stabilizing effectiveness of 2-(2-hydroxy-3,5-di-.alpha.-cumylphenyl)-2H-benzotriazole and which is soluble in the new environmentally approved solvents is required. The several compounds mentioned earlier in this paragraph meet or essentially meet these new requirements.
Japanese Kokai 75/158588 describes the preparation of 2-(2-hydroxy-3-.alpha.-cumyl-5-methylphenyl)-2H-benzotriazole and 2-(2-hydroxy-3-methyl-5-.alpha.-cumylphenyl)-2H-benzotriazole as effective UV absorbers.
U.S. Pat. No. 4,283,327 discloses the preparation of 2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole and 5-chloro-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole. U.S. Pat. Nos. 4,587,346; 4,675,352; 4,973,701; 5,095,062 and 5,240,975 describe the preparation of liquid benzotriazole mixtures by the post alkylation of preformed benzotriazoles using higher alkenes and an acid catalyst. Such products are complex liquid mixtures of various related benzotriazoles and are soluble in the environmentally acceptable solvents. However, while these UV absorbers are quite soluble in environmentally acceptable solvents, they do not have the thermal stability of the benzotriazole compounds which are substituted in the 3-position by an .alpha.-cumyl moiety.
The instant benzotfiazole compounds are substituted in the 3-position with a .alpha.-cumyl group and in the 5-position usually with either a mixture with various alkylated moieties as substituents or are single compounds substituted with one bulky, tert-alkyl group. These materials are more soluble in common coatings solvents than the tris-aryl-s-triazines that are functionalized with simple alkyl groups. Common coatings solvents include xylene, methyl amyl ketone, butyl cellosolve, butyl carbitol and methyl isobutyl ketone. This functionality in combination with the high molecular weight of the compounds provides the instant compounds with a low migratory propensity when incorporated into the base coat of a clear coat/base coat system.